In a first type of shooting system, a cartridge with compressed gas, such as carbon dioxide, is used only as a source of energy for propelling the projectile. In such systems, the compressed gas is released to provide the energy source for acceleration of a separate projectile, such as a bullet, a pellet or the like. U.S. Pat. No. 2,375,314 (Mills) describes a device that uses a cartridge containing a compressed fluid for propelling a projectile. The compressed fluid is released from the cartridge and the pressure of the gas propels the projectile from the barrel. In this device, the cartridge remains in the device after launching of the projectile. The cartridge is held in place by a plate to prevent the cartridge from exiting the barrel during launching of the projectile. Annular gaskets are disposed on the outside of the projectile which, in turn, are snugly positioned within the barrel to contain the released fluid. Such a system does not use the cartridge as a projectile. In systems that use the cartridge only as a source of energy and not as a projectile, the problem of holding the cartridge in the barrel can be solved by bumps or dimples in the barrel as shown in Mills.
These shooting systems require high precision machining and molding for valves, pipes, mechanical parts, and projectiles. In addition, the material contained in the cartridge is not used in the process of shooting and is discarded after exhausting the gas contained in the cartridge.
In a second type of shooting system, a cartridge containing compressed gas is used both as a source of energy and as a part of the projectile. This system has difficulty holding the cartridge in a fixed position in a barrel prior to and during the moment of activation of the cartridge and then allowing the cartridge to move forward after activation. Second, the loss of gas between the bore of the barrel and the outside of the cartridge reduces the efficiency of the shooting system. U.S. Pat. No. 3,417,719 (Nitenson) describes an underwater gun in which a projectile is held in frictional engagement with the barrel by using a shank that holds the projectile in a frictional fit. A special shoulder of the cartridge overcomes the frictional force applied by the shank during activation of the projectile. The underwater gun of Nitenson requires strict dimensional tolerances of the cartridge and the bore of the barrel to reduce the release of gas during firing of the projectile.
U.S. Pat. No. 2,588,184 (Walsh) describes a system that uses inefficient rocket principles for compulsion and the outflowing of gases forbid the launching to occur from the hand of the operator because of the dangerous gases.
Using the cartridge only as a source of energy results in simpler constructions than the underwater guns described above for Nitenson, but these constructions are unusable when the cartridges are both a source of energy and a projectile because the cartridge moves forward after deactivation and the bumps prevent such movement of the cartridge. In fact, such movement of the cartridge is not intended by such systems and the cartridge is intended to be used only as an energy source.
A new approach to the method and devices for shooting using compressed gas is desired.
It is desirable to have a shooting system in which a cartridge containing the source of energy also functions as the projectile, and in such systems the use of the source of energy is increased by reducing the loss of resultant gases from exiting the barrel prior to disengagement of the projectile. It is also desirable to have a simple construction for a shooting system.